Technical Field
The present invention relates to cross-linked terpolymers. More particularly, the present invention relates to cross-linked terpolymers containing polymerized units of phenol, formaldehyde and alkyldiamine monomers, methods of preparing the terpolymers, and a method of removing metal ions from an aqueous solution by adsorbing the metal ions with the terpolymers, which is also used for treatment of real wastewater samples.
Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Toxic metal ions, such as lead (Pb2+) have attracted a large attention and importance in recent years due to its hazardous effect on the human health and environment [C. Dulcy Evangelin, S. G. Gunasekaran, M. Dharmendirakumar, Asia-Pac. J. Chem. Eng. 8 (2013) 189-201; A. Atia, M. Donia, A. M. Yousif, Sep. Purif. Technol. 61 (2008) 348-357; S. Mahdavi, M. Jalali, A. Afkhami, Chem. Eng. Commun. 200 (2013) 448-470—each incorporated herein by reference in its entirety]. The toxicity of lead arises from its non-biodegradable nature and can accumulate in the human body and cause hazardous effects, such as, nerve damage, anaemia, retarded foetal growth. Other effects are seen in children as they absorb and digest larger amounts of Pb2+ ions than adults [P. L. Reagan, E. K. Silbergeld, (1989). Establishing a health based standard for lead in residential soils. In: Hemphill and Cothern, eds. Trace substances in environmental health, Supplement to Volume 12, (1990) of Environmental Geochemistry and Health—incorporated herein by reference in its entirety].
Several treatment methods have been utilized for the removal of heavy metal ions such as lead ions from aqueous solutions. Among these methods, adsorption is considered effective and economical. The adsorption by cross-linked polymers possesses flexibility in design and application as the cross-linked polymer can be functionalized by different chelating groups, regenerated and reused [A. Jakubiak, I. A. Owsik, B. N. Kolarz, React. Funct. Polym. 65 (2005) 161-167; B. N. Kolarz, A. Jakubiak, J. Jezierska, B. Dach, React. Funct. Polym. 68 (2008) 1207-1217; M. R. Maurya, S. Sikarwar, T. Joseph, P. Manikandan, S. B. Hlligudi, React. Funct. Polym. 65 (2005) 71-83; K. C. Gupta, A. K. Sutar, Polym. Adv. Technol. 19 (2008)186-200; K. C. Gupta, A. K. Sutar React. Funct. Polym. 68 (2008)12-26; M. Ruiz, A. M. Sastre, E. Guibal, React. Funct. Polym. 45 (2000)155-173; F. Fu, Q. Wang, J. Environ. Manage. 92 (2011) 407-418—each incorporated herein by reference in its entirety].
One class of cross-linked polymers is the phenol-formaldehyde polymer. Phenol-formaldehyde polymers can be modified to produce ion exchange resins with a variety of functional groups [F. Lawson and W. H. Jay. Ion exchange resin. U.S. Pat. No. 6,203,708, assigned to Monash University (Clayton, AU), Mar. 20, 2001—incorporated herein by reference in its entirety]. Phenol-formaldehyde polymers containing oxime chelating groups showed high adsorption capacity toward Cu2+ ion removal [K. A. K. Ebraheem, S. T. Hamdi, React. Funct. Polym. 34 (1997) 5-10—incorporated herein by reference in its entirety], A salicylic acid-formaldehyde-catechol terpolymeric resin has been evaluated for the removal of Ni(II), Cu(II), Zn(II), Pb(II) and Cd(II) ions [R. R. Bhatt, B. A. Shah, (2013) Arab. J. Chem., http://dx.doi.org/10.1016/j.arabjc.2013.03.012 “in press”—incorporated herein by reference in its entirety], an anthranilic acid-formaldehyde-2-aminopyridine terpolymer has been synthesized and evaluated for the removal of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pb(II) [R. S. Azarudeen, R. Subha, D. Jeyakumar, A. R. Burkanudeen, Sep. Purif. Technol. 116 (2013) 366-377—incorporated herein by reference in its entirety].
Polymeric material based on phenol-formaldehyde can be used in a variety of applications. Such applications include insulation material, consolidated wood products, oil filters, abrasive binders, ion exchange membranes and carbon membranes upon carbonization [F. C. Dupre, M. E. Foucht, W. P. Freese, K. D. Gabrielson, B. D. Gapud, W. H. Ingram, T. M. McVay, R. A. Rediger, K. A. Shoemake, K. K. Tutin, J. T. Wright, Cyclic urea-formaldehyde prepolymer for use in phenolformaldehyde and melamine-formaldehyde resin-based binders. U.S. Pat. No. 6,379,814, assigned to Georgia-Pacific Resins, Inc. (Atlanta, Ga.), Apr. 30, 2002; K. Lenghaus, G. G. Qiao, D. H. Solomon, Polymer 42 (2001) 3355-3362; N. Kishore, S. Sachan, K. N. Rai, A. Kumar, Carbon 41 (2003) 2961-2972—each incorporated herein by reference in its entirety].
There is a continuing need in the resin art for resins or polymers with novel monomers or novel combinations of monomers, to provide enhanced ion adsorption capacity and/or ion selectivity.